I'm triggering a soft synth with an external keyboard connected to a midi hub (connected via usb to computer). I don't remember having to do this with X3 but now with SPlat I get terrible latency unless I turn on PDC. If I bypass all effects the latency goes away as well. There must be something I'm not understanding, I don't have any other plug-ins on the track with the soft synth or master bus. As a side note I also get the latency when using the virtual keyboard to trigger the synth (with PDC turned off). Also this happens with all soft synths.  thanks -Jim

jimo
There must be something I'm not understanding, I don't have any other plug-ins on the track with the soft synth or master bus.

When it comes to PDC, plug-ins on ANY track or bus affect ALL tracks and busses otherwise everything would be of sync. This has always been the case.

To clarify: pushing the PDC button so it lights up *turns it off*, so your latency goes away.
 
Strangely, it's the opposite with the oversampling button (labelled "x2"). Pushing that so it lights up turns it on.

WalkerTalker
To clarify: pushing the PDC button so it lights up *turns it off*, so your latency goes away.
 
Strangely, it's the opposite with the oversampling button (labelled "x2"). Pushing that so it lights up turns it on.

Good point and thanks for the clarification. So yes I push the button so (my mistake) it turns off PDC to get rid of the latency. The problem also with having to do this while recording midi is that then of course the notes don't line up on the grid. I guess this brings up a more general question of PDC. So its on be default but do you really need it on unless you are tracking instruments through a plugin?

The PDC [Bypass] button doesn't 'turn off' PDC per se; it disables compensation only on Input-monitored tracks, which include synth tracks. Other tracks and the metronome are still delayed to sync with the track/bus that has the delay-inducing plugin on it), so any MIDI you record will be laid down late since you're playing to a delayed click. Audio recording, on the other hand, gets compensated for the added latency after the fact so it will sync on playback when input monitoring is disabled and/or PDC bypass is disengaged.